While the digital audio and video technology enters the high resolution time, the Three Dimension (3D) stereoscopic display technology has been drawn the attention and favor of the people data by day. The naked eye 3D technology gets rid of the complicated accessory equipments and goes over big. There are kinds of technologies to realize the naked eye 3D display, such as optical grating, liquid crystal lens, most of which at present is mainly based on special division of subpixels. Such method leads to the decreased 3D image resolution of the display panel in comparison with 2D panels. The 3D effect is totally far from perfection, suffering low image resolutions. Moreover, the adding 3D modules pose negative effect on the 2D display effect as well, which is totally unacceptable.
The principle of the liquid crystal lens is to utilize the birefringence of the liquid crystal molecules, and the director alignment distribution with the electrical field to make the light beam be focused or diffused. By changing the voltage to control the alignment direction of the liquid crystal molecules, and the corresponding effective refractive index distribution, the 3D display is realized. As shown in FIG. 1, which shows a structure diagram of a 3D display device according to prior art, comprising a display panel 8, and a liquid crystal lens located on the display panel 8. The liquid crystal lens comprises: an upper glass substrate 2 and a lower glass substrate 6, a liquid crystal layer 4 located between the upper glass substrate 2 and the lower glass substrate 6, a liquid crystal lens polarizer 1 located on one side of the upper glass substrate 2 away from the lower glass substrate 6, a common electrode 3 located on the upper glass substrate 2 close to the lower glass substrate 6, a plurality of strip lens electrodes 5 which are separately distributed on one side of the lower glass substrate 6 close to the upper glass substrate 2; the 3D display device applies various bias voltages to the plurality of strip lens electrodes 5 to make the liquid crystal molecules in the liquid crystal layer 4 have different tilt degrees, wherein the voltage at the border is higher, and the voltage in the middle is lower so that the refractive index of the liquid crystal layer 4 gradually decreases from the middle to the border to form the lens effect. The variation of the refractive index makes the liquid crystal layer 4 function as an optical lens to realize the 3D image display.
To obtain ideal display result, theoretically, it is required that the alignment direction of the liquid crystal molecules and the illuminating light polarization direction of the bottom liquid crystal display device are completely consistent, and thus to realize the complete extraordinary light (e light) 3D image. However, for reducing the influence of the Moire pattern to the display result, as shown in FIG. 2, the alignment of the liquid crystal lens relative to the display pixels is generally arranged to be tilted; and because the bias voltages of the various strip lens electrodes 5 are different, the transverse electrical field component can be easily formed among the strip lens electrodes 5, and the direction of the transverse component and the theoretical twist direction are not consistent, which results in that the liquid crystal molecules will deviate from the original alignment direction. Thus, the ordinary light (o light) 2D image of certain level will be formed. Due to the larger voltage variation at the border of the liquid crystal lens, such issue becomes more serious. The o light in the liquid crystal lens does not have the lens effect, and thus to have the 2D interference signal to reduce the 3D display result. Generally, for solving the issue, it is needed that the additive polarizer is adhered to the surface of the liquid crystal lens, again for filtering the o light (i.e. the liquid crystal lens polarizer 1), so that the liquid crystal lens thickness, of which it has been thick itself due to top and bottom glass structures, keeps increasing, and it is against the development trend for thinner display devices.
The metal wire grid is a periodic metal and dielectric layer arrangement structure, which has the extremely high extinction ratio for the Transverse Magnetic (TM) and the Transverse Electric (TE) and can obviously pass the TM light perpendicular with the metal wire alignment direction and reflect the TE light parallel with the metal wire alignment direction. Therefore, it can be used for an ideal polarizer. Because the thickness is merely at the nanometer scale and the manufacture process has been mature gradually, it draws lots of attentions.